Network Working Group V. Fuller
Internet-Draft D. Farinacci
Obsoletes: 6833 (if approved) Cisco Systems
Intended status: Standards Track A. Cabellos (Ed.)
Expires: April 24, 2019 UPC/BarcelonaTech
October 21, 2018
Locator/ID Separation Protocol (LISP) Control-Plane
draft-ietf-lisp-rfc6833bis-19
Abstract
This document describes the Control-Plane and Mapping Service for the
Locator/ID Separation Protocol (LISP), implemented by two new types
of LISP-speaking devices -- the LISP Map-Resolver and LISP Map-Server
-- that provides a simplified "front end" for one or more Endpoint ID
to Routing Locator mapping databases.
By using this Control-Plane service interface and communicating with
Map-Resolvers and Map-Servers, LISP Ingress Tunnel Routers (ITRs) and
Egress Tunnel Routers (ETRs) are not dependent on the details of
mapping database systems, which facilitates modularity with different
database designs. Since these devices implement the "edge" of the
LISP Control-Plane infrastructure, connecting EID addressable nodes
of a LISP site, their implementation and operational complexity
reduces the overall cost and effort of deploying LISP.
This document obsoletes RFC 6830 and 6833.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 24, 2019.
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Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Scope of Applicability . . . . . . . . . . . . . . . . . 4
2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 5
3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 5
4. Basic Overview . . . . . . . . . . . . . . . . . . . . . . . 6
5. LISP IPv4 and IPv6 Control-Plane Packet Formats . . . . . . . 8
5.1. LISP Control Packet Type Allocations . . . . . . . . . . 11
5.2. Map-Request Message Format . . . . . . . . . . . . . . . 12
5.3. EID-to-RLOC UDP Map-Request Message . . . . . . . . . . . 15
5.4. Map-Reply Message Format . . . . . . . . . . . . . . . . 17
5.5. EID-to-RLOC UDP Map-Reply Message . . . . . . . . . . . . 21
5.6. Map-Register Message Format . . . . . . . . . . . . . . . 24
5.7. Map-Notify/Map-Notify-Ack Message Format . . . . . . . . 27
5.8. Encapsulated Control Message Format . . . . . . . . . . . 29
6. Changing the Contents of EID-to-RLOC Mappings . . . . . . . . 31
6.1. Solicit-Map-Request (SMR) . . . . . . . . . . . . . . . . 31
7. Routing Locator Reachability . . . . . . . . . . . . . . . . 32
7.1. RLOC-Probing Algorithm . . . . . . . . . . . . . . . . . 34
8. Interactions with Other LISP Components . . . . . . . . . . . 35
8.1. ITR EID-to-RLOC Mapping Resolution . . . . . . . . . . . 35
8.2. EID-Prefix Configuration and ETR Registration . . . . . . 36
8.3. Map-Server Processing . . . . . . . . . . . . . . . . . . 38
8.4. Map-Resolver Processing . . . . . . . . . . . . . . . . . 39
8.4.1. Anycast Operation . . . . . . . . . . . . . . . . . . 39
9. Security Considerations . . . . . . . . . . . . . . . . . . . 40
10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 41
11. Changes since RFC 6833 . . . . . . . . . . . . . . . . . . . 42
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 42
12.1. LISP UDP Port Numbers . . . . . . . . . . . . . . . . . 43
12.2. LISP Packet Type Codes . . . . . . . . . . . . . . . . . 43
12.3. LISP ACT and Flag Fields . . . . . . . . . . . . . . . . 43
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12.4. LISP Address Type Codes . . . . . . . . . . . . . . . . 44
12.5. LISP Algorithm ID Numbers . . . . . . . . . . . . . . . 44
12.6. LISP Bit Flags . . . . . . . . . . . . . . . . . . . . . 45
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 48
13.1. Normative References . . . . . . . . . . . . . . . . . . 48
13.2. Informative References . . . . . . . . . . . . . . . . . 49
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 53
Appendix B. Document Change Log . . . . . . . . . . . . . . . . 53
B.1. Changes to draft-ietf-lisp-rfc6833bis-18 . . . . . . . . 53
B.2. Changes to draft-ietf-lisp-rfc6833bis-18 . . . . . . . . 53
B.3. Changes to draft-ietf-lisp-rfc6833bis-17 . . . . . . . . 53
B.4. Changes to draft-ietf-lisp-rfc6833bis-16 . . . . . . . . 54
B.5. Changes to draft-ietf-lisp-rfc6833bis-15 . . . . . . . . 54
B.6. Changes to draft-ietf-lisp-rfc6833bis-14 . . . . . . . . 54
B.7. Changes to draft-ietf-lisp-rfc6833bis-13 . . . . . . . . 54
B.8. Changes to draft-ietf-lisp-rfc6833bis-12 . . . . . . . . 54
B.9. Changes to draft-ietf-lisp-rfc6833bis-11 . . . . . . . . 54
B.10. Changes to draft-ietf-lisp-rfc6833bis-10 . . . . . . . . 55
B.11. Changes to draft-ietf-lisp-rfc6833bis-09 . . . . . . . . 55
B.12. Changes to draft-ietf-lisp-rfc6833bis-08 . . . . . . . . 55
B.13. Changes to draft-ietf-lisp-rfc6833bis-07 . . . . . . . . 55
B.14. Changes to draft-ietf-lisp-rfc6833bis-06 . . . . . . . . 56
B.15. Changes to draft-ietf-lisp-rfc6833bis-05 . . . . . . . . 56
B.16. Changes to draft-ietf-lisp-rfc6833bis-04 . . . . . . . . 56
B.17. Changes to draft-ietf-lisp-rfc6833bis-03 . . . . . . . . 57
B.18. Changes to draft-ietf-lisp-rfc6833bis-02 . . . . . . . . 57
B.19. Changes to draft-ietf-lisp-rfc6833bis-01 . . . . . . . . 57
B.20. Changes to draft-ietf-lisp-rfc6833bis-00 . . . . . . . . 57
B.21. Changes to draft-farinacci-lisp-rfc6833bis-00 . . . . . . 57
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 58
1. Introduction
The Locator/ID Separation Protocol [I-D.ietf-lisp-rfc6830bis] (see
also [I-D.ietf-lisp-introduction]) specifies an architecture and
mechanism for dynamic tunneling by logically separating the addresses
currently used by IP in two separate name spaces: Endpoint IDs
(EIDs), used within sites; and Routing Locators (RLOCs), used on the
transit networks that make up the Internet infrastructure. To
achieve this separation, LISP defines protocol mechanisms for mapping
from EIDs to RLOCs. In addition, LISP assumes the existence of a
database to store and propagate those mappings across mapping system
nodes. Several such databases have been proposed; among them are the
Content distribution Overlay Network Service for LISP-NERD (a Not-so-
novel EID-to-RLOC Database) [RFC6837], LISP Alternative Logical
Topology (LISP-ALT) [RFC6836], and LISP Delegated Database Tree
(LISP-DDT) [RFC8111].
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The LISP Mapping Service defines two new types of LISP-speaking
devices: the Map-Resolver, which accepts Map-Requests from an Ingress
Tunnel Router (ITR) and "resolves" the EID-to-RLOC mapping using a
mapping database; and the Map-Server, which learns authoritative EID-
to-RLOC mappings from an Egress Tunnel Router (ETR) and publishes
them in a database.
This LISP Control-Plane Mapping Service can be used by many different
encapsulation-based or translation-based Data-Planes which include
but are not limited to the ones defined in LISP RFC 6830bis
[I-D.ietf-lisp-rfc6830bis], LISP-GPE [I-D.ietf-lisp-gpe], VXLAN
[RFC7348], VXLAN-GPE [I-D.ietf-nvo3-vxlan-gpe], GRE [RFC2890], GTP
[GTP-3GPP], ILA [I-D.herbert-intarea-ila], and Segment Routing (SRv6)
[RFC8402].
Conceptually, LISP Map-Servers share some of the same basic
configuration and maintenance properties as Domain Name System (DNS)
[RFC1035] servers; likewise, Map-Resolvers are conceptually similar
to DNS caching resolvers. With this in mind, this specification
borrows familiar terminology (resolver and server) from the DNS
specifications.
Note this document doesn't assume any particular database mapping
infrastructure to illustrate certain aspects of Map-Server and Map-
Resolver operation. The Mapping Service interface can (and likely
will) be used by ITRs and ETRs to access other mapping database
systems as the LISP infrastructure evolves.
LISP is not intended to address problems of connectivity and scaling
on behalf of arbitrary communicating parties. Relevant situations
are described in the scoping section of the introduction to
[I-D.ietf-lisp-rfc6830bis].
This document obsoletes RFC 6830 and 6833.
1.1. Scope of Applicability
LISP was originally developed to address the Internet-wide route
scaling problem [RFC4984].. While there are a number of approaches
of interest for that problem, as LISP as been developed and refined,
a large number of other LISP uses have been found and are being used.
As such, the design and development of LISP has changed so as to
focus on these use cases. The common property of these uses is a
large set of cooperating entities seeking to communicate over the
public Internet or other large underlay IP infrastructures, while
keeping the addressing and topology of the cooperating entities
separate from the underlay and Internet topology, routing, and
addressing.
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2. Requirements Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Definition of Terms
Map-Server: A network infrastructure component that learns of EID-
Prefix mapping entries from an ETR, via the registration mechanism
described below, or some other authoritative source if one exists.
A Map-Server publishes these EID-Prefixes in a mapping database.
Map-Request: A LISP Map-Request is a Control-Plane message to query
the mapping system to resolve an EID. A LISP Map-Request can also
be sent to an RLOC to test for reachability and to exchange
security keys between an encapsulator and a decapsulator. This
type of Map-Request is also known as an RLOC-Probe Request.
Map-Reply: A LISP Map-Reply is a Control-Plane message returned in
response to a Map-Request sent to the mapping system when
resolving an EID. A LISP Map-Reply can also be returned by a
decapsulator in response to a Map-Request sent by an encapsulator
to test for reachability. This type of Map-Reply is known as a
RLOC-Probe Reply.
Encapsulated Map-Request: A LISP Map-Request carried within an
Encapsulated Control Message (ECM), which has an additional LISP
header prepended. Sent to UDP destination port 4342. The "outer"
addresses are routable IP addresses, also known as RLOCs. Used by
an ITR when sending to a Map-Resolver and by a Map-Server when
forwarding a Map-Request to an ETR.
Map-Resolver: A network infrastructure component that accepts LISP
Encapsulated (ECM) Map-Requests, typically from an ITR, and
determines whether or not the destination IP address is part of
the EID namespace; if it is not, a Negative Map-Reply is returned.
Otherwise, the Map-Resolver finds the appropriate EID-to-RLOC
mapping by consulting a mapping database system.
Negative Map-Reply: A LISP Map-Reply that contains an empty
Locator-Set. Returned in response to a Map-Request if the
destination EID is not registered in the mapping system, is policy
denied or fails authentication.
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Map-Register message: A LISP message sent by an ETR to a Map-Server
to register its associated EID-Prefixes. In addition to the set
of EID-Prefixes to register, the message includes one or more
RLOCs to reach ETR(s). The Map-Server uses these RLOCs when
forwarding Map-Requests (re-formatted as Encapsulated Map-
Requests). An ETR MAY request that the Map-Server answer Map-
Requests on its behalf by setting the "proxy Map-Reply" flag
(P-bit) in the message.
Map-Notify message: A LISP message sent by a Map-Server to an ETR
to confirm that a Map-Register has been received and processed.
An ETR requests that a Map-Notify be returned by setting the
"want-map-notify" flag (M-bit) in the Map-Register message.
Unlike a Map-Reply, a Map-Notify uses UDP port 4342 for both
source and destination. Map-Notify messages are also sent to ITRs
by Map-Servers when there are RLOC-set changes.
For definitions of other terms, notably Ingress Tunnel Router (ITR),
Egress Tunnel Router (ETR), and Re-encapsulating Tunnel Router (RTR),
refer to the LISP Data-Plane specification
[I-D.ietf-lisp-rfc6830bis].
4. Basic Overview
A Map-Server is a device that publishes EID-Prefixes in a LISP
mapping database on behalf of a set of ETRs. When it receives a Map
Request (typically from an ITR), it consults the mapping database to
find an ETR that can answer with the set of RLOCs for an EID-Prefix.
To publish its EID-Prefixes, an ETR periodically sends Map-Register
messages to the Map-Server. A Map-Register message contains a list
of EID-Prefixes plus a set of RLOCs that can be used to reach the
ETRs.
When LISP-ALT [RFC6836] is used as the mapping database, a Map-Server
connects to the ALT network and acts as a "last-hop" ALT-Router.
Intermediate ALT-Routers forward Map-Requests to the Map-Server that
advertises a particular EID-Prefix, and the Map-Server forwards them
to the owning ETR, which responds with Map-Reply messages.
When LISP-DDT [RFC8111] is used as the mapping database, a Map-Server
sends the final Map-Referral messages from the Delegated Database
Tree.
A Map-Resolver receives Encapsulated Map-Requests from its client
ITRs and uses a mapping database system to find the appropriate ETR
to answer those requests. On a LISP-ALT network, a Map-Resolver acts
as a "first-hop" ALT-Router. It has Generic Routing Encapsulation
(GRE) tunnels configured to other ALT-Routers and uses BGP to learn
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paths to ETRs for different prefixes in the LISP-ALT database. The
Map-Resolver uses this path information to forward Map-Requests over
the ALT to the correct ETRs. On a LISP-DDT network [RFC8111], a Map-
Resolver maintains a referral-cache and acts as a "first-hop" DDT-
node. The Map-Resolver uses the referral information to forward Map-
Requests.
Note that while it is conceivable that a Map-Resolver could cache
responses to improve performance, issues surrounding cache management
will need to be resolved so that doing so will be reliable and
practical. As initially deployed, Map-Resolvers will operate only in
a non-caching mode, decapsulating and forwarding Encapsulated Map
Requests received from ITRs. Any specification of caching
functionality is out of scope for this document.
Note that a single device can implement the functions of both a Map-
Server and a Map-Resolver, and in many cases the functions will be
co-located in that way. Also, there can be ALT-only nodes and DDT-
only nodes, when LISP-ALT and LISP-DDT are used, respectively, to
connecting Map-Resolvers and Map-Servers together to make up the
Mapping System.
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5. LISP IPv4 and IPv6 Control-Plane Packet Formats
The following UDP packet formats are used by the LISP control plane.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| IHL |Type of Service| Total Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identification |Flags| Fragment Offset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Time to Live | Protocol = 17 | Header Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Routing Locator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Routing Locator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port | Dest Port |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| LISP Message |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv4 UDP LISP Control Message
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Traffic Class | Flow Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Length | Next Header=17| Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Source Routing Locator +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Destination Routing Locator +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port | Dest Port |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| LISP Message |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv6 UDP LISP Control Message
When a UDP Map-Request, Map-Register, or Map-Notify (when used as a
notification message) are sent, the UDP source port is chosen by the
sender and the destination UDP port number is set to 4342. When a
UDP Map-Reply, Map-Notify (when used as an acknowledgement to a Map-
Register), or Map-Notify-Ack are sent, the source UDP port number is
set to 4342 and the destination UDP port number is copied from the
source port of either the Map-Request or the invoking data packet.
Implementations MUST be prepared to accept packets when either the
source port or destination UDP port is set to 4342 due to NATs
changing port number values.
The 'UDP Length' field will reflect the length of the UDP header and
the LISP Message payload. Implementations should follow the
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procedures from [RFC8085] to determine the maximum size used for any
LISP control message.
The UDP checksum is computed and set to non-zero for all messages
sent to or from port 4342. It MUST be checked on receipt, and if the
checksum fails, the control message MUST be dropped [RFC1071].
The format of control messages includes the UDP header so the
checksum and length fields can be used to protect and delimit message
boundaries.
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5.1. LISP Control Packet Type Allocations
This section defines the LISP control message formats and summarizes
for IANA the LISP Type codes assigned by this document. For
completeness, the summary below includes the LISP Shared Extension
Message assigned by [RFC8113]. Message type definitions are:
Reserved: 0 b'0000'
LISP Map-Request: 1 b'0001'
LISP Map-Reply: 2 b'0010'
LISP Map-Register: 3 b'0011'
LISP Map-Notify: 4 b'0100'
LISP Map-Notify-Ack: 5 b'0101'
LISP Map-Referral: 6 b'0110'
Not Assigned 7 b'0111'
LISP Encapsulated Control Message: 8 b'1000'
Not Assigned 9-14 b'1001'- b'1110'
LISP Shared Extension Message: 15 b'1111' [RFC8113]
Values in the "Not Assigned" range can be assigned according to
procedures in [RFC8126].
Protocol designers experimenting with new message formats are
recommended to use the LISP Shared Extension Message Type described
in [RFC8113].
All LISP Control-Plane messages use Address Family Identifiers (AFI)
[AFI] or LISP Canonical Address Format (LCAF) [RFC8060] formats to
encode either fixed or variable length addresses. This includes
explicit fields in each control message or part of EID-records or
RLOC-records in commonly formatted messages.
The LISP control-plane describes how other data-planes can encode
messages to support the Soliciting of Map-Requests as well as RLOC-
probing procedures.
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5.2. Map-Request Message Format
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=1 |A|M|P|S|p|s|R|R| Rsvd |L|D| IRC | Record Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . . . Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source-EID-AFI | Source EID Address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ITR-RLOC-AFI 1 | ITR-RLOC Address 1 ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ITR-RLOC-AFI n | ITR-RLOC Address n ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Reserved | EID mask-len | EID-Prefix-AFI |
Rec +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | EID-Prefix ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Map-Reply Record ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Packet field descriptions:
Type: 1 (Map-Request)
A: This is an authoritative bit, which is set to 0 for UDP-based Map-
Requests sent by an ITR. It is set to 1 when an ITR wants the
destination site to return the Map-Reply rather than the mapping
database system returning a Map-Reply.
M: This is the map-data-present bit. When set, it indicates that a
Map-Reply Record segment is included in the Map-Request.
P: This is the probe-bit, which indicates that a Map-Request SHOULD
be treated as a Locator reachability probe. The receiver SHOULD
respond with a Map-Reply with the probe-bit set, indicating that
the Map-Reply is a Locator reachability probe reply, with the
nonce copied from the Map-Request. See RLOC-Probing Section 7.1
for more details. This RLOC-probe Map-Request MUST not be sent to
the mapping system. If a Map-Resolver or Map-Server receives a
Map-Request with the probe-bit set, it MUST drop the message.
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S: This is the Solicit-Map-Request (SMR) bit. See Solicit-Map-
Request (SMRs) Section 6.1 for details.
p: This is the PITR bit. This bit is set to 1 when a PITR sends a
Map-Request.
s: This is the SMR-invoked bit. This bit is set to 1 when an xTR is
sending a Map-Request in response to a received SMR-based Map-
Request.
R: This reserved bit MUST be set to 0 on transmit and MUST be ignored
on receipt.
Rsvd: This field MUST be set to 0 on transmit and MUST be ignored on
receipt.
L: This is the local-xtr bit. It is used by an xTR in a LISP site to
tell other xTRs in the same site that it is part of the RLOC-set
for the LISP site. The L-bit is set to 1 when the RLOC is the
sender's IP address.
D: This is the dont-map-reply bit. It is used in the SMR procedure
described in Section 6.1. When an xTR sends an SMR Map-Request
message, it doesn't need a Map-Reply returned. When this bit is
set, the receiver of the Map-Request does not return a Map-Reply.
IRC: This 5-bit field is the ITR-RLOC Count, which encodes the
additional number of ('ITR-RLOC-AFI', 'ITR-RLOC Address') fields
present in this message. At least one (ITR-RLOC-AFI, ITR-RLOC-
Address) pair MUST be encoded. Multiple 'ITR-RLOC Address' fields
are used, so a Map-Replier can select which destination address to
use for a Map-Reply. The IRC value ranges from 0 to 31. For a
value of 0, there is 1 ITR-RLOC address encoded; for a value of 1,
there are 2 ITR-RLOC addresses encoded, and so on up to 31, which
encodes a total of 32 ITR-RLOC addresses.
Record Count: This is the number of records in this Map-Request
message. A record is comprised of the portion of the packet that
is labeled 'Rec' above and occurs the number of times equal to
Record Count. For this version of the protocol, a receiver MUST
accept and process Map-Requests that contain one or more records,
but a sender MUST only send Map-Requests containing one record.
Support for processing multiple EIDs in a single Map-Request
message will be specified in a future version of the protocol.
Nonce: This is an 8-octet random value created by the sender of the
Map-Request. This nonce will be returned in the Map-Reply. The
security of the LISP mapping protocol critically depends on the
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strength of the nonce in the Map-Request message. The nonce MUST
be generated by a properly seeded pseudo-random (or strong random)
source. See [RFC4086] for advice on generating security-sensitive
random data.
Source-EID-AFI: This is the address family of the 'Source EID
Address' field.
Source EID Address: This is the EID of the source host that
originated the packet that caused the Map-Request. When Map-
Requests are used for refreshing a Map-Cache entry or for RLOC-
Probing, an AFI value 0 is used and this field is of zero length.
ITR-RLOC-AFI: This is the address family of the 'ITR-RLOC Address'
field that follows this field.
ITR-RLOC Address: This is used to give the ETR the option of
selecting the destination address from any address family for the
Map-Reply message. This address MUST be a routable RLOC address
of the sender of the Map-Request message.
EID mask-len: This is the mask length for the EID-Prefix.
EID-Prefix-AFI: This is the address family of the EID-Prefix
according to [AFI] and [RFC8060].
EID-Prefix: This prefix address length is 4 octets for an IPv4
address family and 16 octets for an IPv6 address family when the
EID-Prefix-AFI is 1 or 2, respectively. For other AFIs [AFI], the
address length varies and for the LCAF AFI the format is defined
in [RFC8060]. When a Map-Request is sent by an ITR because a data
packet is received for a destination where there is no mapping
entry, the EID-Prefix is set to the destination IP address of the
data packet, and the 'EID mask-len' is set to 32 or 128 for IPv4
or IPv6, respectively. When an xTR wants to query a site about
the status of a mapping it already has cached, the EID-Prefix used
in the Map-Request has the same mask-length as the EID-Prefix
returned from the site when it sent a Map-Reply message.
Map-Reply Record: When the M-bit is set, this field is the size of a
single "Record" in the Map-Reply format. This Map-Reply record
contains the EID-to-RLOC mapping entry associated with the Source
EID. This allows the ETR that will receive this Map-Request to
cache the data if it chooses to do so.
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5.3. EID-to-RLOC UDP Map-Request Message
A Map-Request is sent from an ITR when it needs a mapping for an EID,
wants to test an RLOC for reachability, or wants to refresh a mapping
before TTL expiration. For the initial case, the destination IP
address used for the Map-Request is the data packet's destination
address (i.e., the destination EID) that had a mapping cache lookup
failure. For the latter two cases, the destination IP address used
for the Map-Request is one of the RLOC addresses from the Locator-Set
of the Map-Cache entry. The source address is either an IPv4 or IPv6
RLOC address, depending on whether the Map-Request is using an IPv4
or IPv6 header, respectively. In all cases, the UDP source port
number for the Map-Request message is a 16-bit value selected by the
ITR/PITR, and the UDP destination port number is set to the well-
known destination port number 4342. A successful Map-Reply, which is
one that has a nonce that matches an outstanding Map-Request nonce,
will update the cached set of RLOCs associated with the EID-Prefix
range.
One or more Map-Request ('ITR-RLOC-AFI', 'ITR-RLOC-Address') fields
MUST be filled in by the ITR. The number of fields (minus 1) encoded
MUST be placed in the 'IRC' field. The ITR MAY include all locally
configured Locators in this list or just provide one locator address
from each address family it supports. If the ITR erroneously
provides no ITR-RLOC addresses, the Map-Replier MUST drop the Map-
Request.
Map-Requests can also be LISP encapsulated using UDP destination
port 4342 with a LISP Type value set to "Encapsulated Control
Message", when sent from an ITR to a Map-Resolver. Likewise, Map-
Requests are LISP encapsulated the same way from a Map-Server to an
ETR. Details on Encapsulated Map-Requests and Map-Resolvers can be
found in Section 5.8.
Map-Requests MUST be rate-limited. It is RECOMMENDED that a Map-
Request for the same EID-Prefix be sent no more than once per second.
However, recommendations from [RFC8085] SHOULD be considered.
An ITR that is configured with mapping database information (i.e., it
is also an ETR) MAY optionally include those mappings in a Map-
Request. When an ETR configured to accept and verify such
"piggybacked" mapping data receives such a Map-Request and it does
not have this mapping in the Map-Cache, it MAY originate a "verifying
Map-Request", addressed to the map-requesting ITR and the ETR MAY add
a Map-Cache entry. If the ETR (when it is an xTR co-located as an
ITR) has a Map-Cache entry that matches the "piggybacked" EID and the
RLOC is in the Locator-Set for the entry, then it MAY send the
"verifying Map-Request" directly to the originating Map-Request
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source. If the RLOC is not in the Locator-Set, then the ETR MUST
send the "verifying Map-Request" to the "piggybacked" EID. Doing
this forces the "verifying Map-Request" to go through the mapping
database system to reach the authoritative source of information
about that EID, guarding against RLOC-spoofing in the "piggybacked"
mapping data.
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5.4. Map-Reply Message Format
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=2 |P|E|S| Reserved | Record Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . . . Nonce |
+-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Record TTL |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
R | Locator Count | EID mask-len | ACT |A| Reserved |
e +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
c | Rsvd | Map-Version Number | EID-Prefix-AFI |
o +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
r | EID-Prefix |
d +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| /| Priority | Weight | M Priority | M Weight |
| L +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| o | Unused Flags |L|p|R| Loc-AFI |
| c +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| \| Locator |
+-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Packet field descriptions:
Type: 2 (Map-Reply)
P: This is the probe-bit, which indicates that the Map-Reply is in
response to a Locator reachability probe Map-Request. The 'Nonce'
field MUST contain a copy of the nonce value from the original
Map-Request. See RLOC-probing Section 7.1 for more details. When
the probe-bit is set to 1 in a Map-Reply message, the A-bit in
each EID-record included in the message MUST be set to 1.
E: This bit indicates that the ETR that sends this Map-Reply message
is advertising that the site is enabled for the Echo-Nonce Locator
reachability algorithm. See Echo-Nonce [I-D.ietf-lisp-rfc6830bis]
for more details.
S: This is the Security bit. When set to 1, the following
authentication information will be appended to the end of the Map-
Reply. The details of signing a Map-Reply message can be found in
[I-D.ietf-lisp-sec].
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AD Type | Authentication Data Content . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Reserved: This field MUST be set to 0 on transmit and MUST be
ignored on receipt.
Record Count: This is the number of records in this reply message.
A record is comprised of that portion of the packet labeled
'Record' above and occurs the number of times equal to Record
Count.
Nonce: This 64-bit value from the Map-Request is echoed in this
'Nonce' field of the Map-Reply.
Record TTL: This is the time in minutes the recipient of the Map-
Reply will store the mapping. If the TTL is 0, the entry MUST be
removed from the cache immediately. If the value is 0xffffffff,
the recipient can decide locally how long to store the mapping.
Locator Count: This is the number of Locator entries. A Locator
entry comprises what is labeled above as 'Loc'. The Locator count
can be 0, indicating that there are no Locators for the EID-
Prefix.
EID mask-len: This is the mask length for the EID-Prefix.
ACT: This 3-bit field describes Negative Map-Reply actions. In any
other message type, these bits are set to 0 and ignored on
receipt. These bits are used only when the 'Locator Count' field
is set to 0. The action bits are encoded only in Map-Reply
messages. They are used to tell an ITR or PITR why a empty
locator-set was returned from the mapping system and how it stores
the map-cache entry.
(0) No-Action: The Map-Cache is kept alive, and no packet
encapsulation occurs.
(1) Natively-Forward: The packet is not encapsulated or dropped
but natively forwarded.
(2) Send-Map-Request: The Map-Cache entry is created and flagged
that any packet matching this entry invokes sending a Map-
Request.
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(3) Drop/No-Reason: A packet that matches this Map-Cache entry is
dropped. An ICMP Destination Unreachable message SHOULD be
sent.
(4) Drop/Policy-Denied: A packet that matches this Map-Cache
entry is dropped. The reason for the Drop action is that a
Map-Request for the target-EID is being policy denied by
either an xTR or the mapping system.
(5) Drop/Authentication-Failure: A packet that matches this Map-
Cache entry is dropped. The reason for the Drop action is
that a Map-Request for the target-EID fails an authentication
verification-check by either an xTR or the mapping system.
A: The Authoritative bit, when set to 1, is always set to 1 by an
ETR. When a Map-Server is proxy Map-Replying for a LISP site, the
Authoritative bit is set to 0. This indicates to requesting ITRs
that the Map-Reply was not originated by a LISP node managed at
the site that owns the EID-Prefix.
Map-Version Number: When this 12-bit value is non-zero, the Map-
Reply sender is informing the ITR what the version number is for
the EID record contained in the Map-Reply. The ETR can allocate
this number internally but MUST coordinate this value with other
ETRs for the site. When this value is 0, there is no versioning
information conveyed. The Map-Version Number can be included in
Map-Request and Map-Register messages. See Map-Versioning
[I-D.ietf-lisp-6834bis] for more details.
EID-Prefix-AFI: Address family of the EID-Prefix according to [AFI]
and [RFC8060].
EID-Prefix: This prefix is 4 octets for an IPv4 address family and
16 octets for an IPv6 address family.
Priority: Each RLOC is assigned a unicast Priority. Lower values
are more preferable. When multiple RLOCs have the same Priority,
they may be used in a load-split fashion. A value of 255 means
the RLOC MUST NOT be used for unicast forwarding.
Weight: When priorities are the same for multiple RLOCs, the Weight
indicates how to balance unicast traffic between them. Weight is
encoded as a relative weight of total unicast packets that match
the mapping entry. For example, if there are 4 Locators in a
Locator-Set, where the Weights assigned are 30, 20, 20, and 10,
the first Locator will get 37.5% of the traffic, the 2nd and 3rd
Locators will get 25% of the traffic, and the 4th Locator will get
12.5% of the traffic. If all Weights for a Locator-Set are equal,
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the receiver of the Map-Reply will decide how to load-split the
traffic. See RLOC-hashing [I-D.ietf-lisp-rfc6830bis] for a
suggested hash algorithm to distribute the load across Locators
with the same Priority and equal Weight values.
M Priority: Each RLOC is assigned a multicast Priority used by an
ETR in a receiver multicast site to select an ITR in a source
multicast site for building multicast distribution trees. A value
of 255 means the RLOC MUST NOT be used for joining a multicast
distribution tree. For more details, see [RFC6831].
M Weight: When priorities are the same for multiple RLOCs, the
Weight indicates how to balance building multicast distribution
trees across multiple ITRs. The Weight is encoded as a relative
weight (similar to the unicast Weights) of the total number of
trees built to the source site identified by the EID-Prefix. If
all Weights for a Locator-Set are equal, the receiver of the Map-
Reply will decide how to distribute multicast state across ITRs.
For more details, see [RFC6831].
Unused Flags: These are set to 0 when sending and ignored on
receipt.
L: When this bit is set, the Locator is flagged as a local Locator to
the ETR that is sending the Map-Reply. When a Map-Server is doing
proxy Map-Replying for a LISP site, the L-bit is set to 0 for all
Locators in this Locator-Set.
p: When this bit is set, an ETR informs the RLOC-Probing ITR that the
locator address for which this bit is set is the one being RLOC-
probed and may be different from the source address of the Map-
Reply. An ITR that RLOC-probes a particular Locator MUST use this
Locator for retrieving the data structure used to store the fact
that the Locator is reachable. The p-bit is set for a single
Locator in the same Locator-Set. If an implementation sets more
than one p-bit erroneously, the receiver of the Map-Reply MUST
select the first set p-bit Locator. The p-bit MUST NOT be set for
Locator-Set records sent in Map-Request and Map-Register messages.
R: This is set when the sender of a Map-Reply has a route to the
Locator in the Locator data record. This receiver may find this
useful to know if the Locator is up but not necessarily reachable
from the receiver's point of view. See also EID-Reachability
Section 7.1 for another way the R-bit may be used.
Locator: This is an IPv4 or IPv6 address (as encoded by the 'Loc-
AFI' field) assigned to an ETR and used by an ITR as a destination
RLOC address in the outer header of a LISP encapsualted packet.
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Note that the destination RLOC address of a LISP encapsulated
packet MAY be an anycast address. A source RLOC of a LISP
encapsulated packet can be an anycast address as well. The source
or destination RLOC MUST NOT be the broadcast address
(255.255.255.255 or any subnet broadcast address known to the
router) and MUST NOT be a link-local multicast address. The
source RLOC MUST NOT be a multicast address. The destination RLOC
SHOULD be a multicast address if it is being mapped from a
multicast destination EID.
5.5. EID-to-RLOC UDP Map-Reply Message
A Map-Reply returns an EID-Prefix with a mask-length that is less
than or equal to the EID being requested. The EID being requested is
either from the destination field of an IP header of a Data-Probe or
the EID record of a Map-Request. The RLOCs in the Map-Reply are
routable IP addresses of all ETRs for the LISP site. Each RLOC
conveys status reachability but does not convey path reachability
from a requester's perspective. Separate testing of path
reachability is required. See RLOC-reachability Section 7.1 for
details.
Note that a Map-Reply MAY contain different EID-Prefix granularity
(prefix + mask-length) than the Map-Request that triggers it. This
might occur if a Map-Request were for a prefix that had been returned
by an earlier Map-Reply. In such a case, the requester updates its
cache with the new prefix information and granularity. For example,
a requester with two cached EID-Prefixes that are covered by a Map-
Reply containing one less-specific prefix replaces the entry with the
less-specific EID-Prefix. Note that the reverse, replacement of one
less-specific prefix with multiple more-specific prefixes, can also
occur, not by removing the less-specific prefix but rather by adding
the more-specific prefixes that, during a lookup, will override the
less-specific prefix.
When an EID moves out of a LISP site [I-D.ietf-lisp-eid-mobility],
the database mapping system may have overlapping EID-prefixes. Or
when a LISP site is configured with multiple sets of ETRs that
support different EID-prefix mask-lengths, the database mapping
system may have overlapping EID-prefixes. When overlapping EID-
prefixes exist, a Map-Request with an EID that best matches any EID-
Prefix MUST be returned in a single Map-Reply message. For instance,
if an ETR had database mapping entries for EID-Prefixes:
2001:db8::/16
2001:db8:1::/24
2001:db8:1:1::/32
2001:db8:1:2::/32
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A Map-Request for EID 2001:db8:1:1::1 would cause a Map-Reply with a
record count of 1 to be returned with a mapping record EID-Prefix of
2001:db8:1:1::/32.
A Map-Request for EID 2001:db8:1:5::5 would cause a Map-Reply with a
record count of 3 to be returned with mapping records for EID-
Prefixes 2001:db8:1::/24, 2001:db8:1:1::/32, 2001:db8:1:2::/32,
filling out the /24 with more-specifics that exist in the mapping
system.
Note that not all overlapping EID-Prefixes need to be returned but
only the more-specific entries (note that in the second example above
2001:db8::/16 was not returned for requesting EID 2001:db8:1:5::5)
for the matching EID-Prefix of the requesting EID. When more than
one EID-Prefix is returned, all SHOULD use the same Time to Live
value so they can all time out at the same time. When a more-
specific EID-Prefix is received later, its Time to Live value in the
Map-Reply record can be stored even when other less-specific entries
exist. When a less-specific EID-Prefix is received later, its Map-
Cache expiration time SHOULD be set to the minimum expiration time of
any more-specific EID-Prefix in the Map-Cache. This is done so the
integrity of the EID-Prefix set is wholly maintained and so no more-
specific entries are removed from the Map-Cache while keeping less-
specific entries.
Map-Replies SHOULD be sent for an EID-Prefix no more often than once
per second to the same requesting router. For scalability, it is
expected that aggregation of EID addresses into EID-Prefixes will
allow one Map-Reply to satisfy a mapping for the EID addresses in the
prefix range, thereby reducing the number of Map-Request messages.
Map-Reply records can have an empty Locator-Set. A Negative Map-
Reply is a Map-Reply with an empty Locator-Set. Negative Map-Replies
convey special actions by the sender to the ITR or PITR that have
solicited the Map-Reply. There are two primary applications for
Negative Map-Replies. The first is for a Map-Resolver to instruct an
ITR or PITR when a destination is for a LISP site versus a non-LISP
site, and the other is to source quench Map-Requests that are sent
for non-allocated EIDs.
For each Map-Reply record, the list of Locators in a Locator-Set MUST
appear in the same order for each ETR that originates a Map-Reply
message. The Locator-Set MUST be sorted in order of ascending IP
address where an IPv4 locator address is considered numerically 'less
than' an IPv6 locator address.
When sending a Map-Reply message, the destination address is copied
from one of the 'ITR-RLOC' fields from the Map-Request. The ETR can
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choose a locator address from one of the address families it
supports. For Data-Probes, the destination address of the Map-Reply
is copied from the source address of the Data-Probe message that is
invoking the reply. The source address of the Map-Reply is one of
the local IP addresses chosen, to allow Unicast Reverse Path
Forwarding (uRPF) checks to succeed in the upstream service provider.
The destination port of a Map-Reply message is copied from the source
port of the Map-Request or Data-Probe, and the source port of the
Map-Reply message is set to the well-known UDP port 4342.
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5.6. Map-Register Message Format
This section specifies the encoding format for the Map-Register
message. The message is sent in UDP with a destination UDP port of
4342 and a randomly selected UDP source port number.
The Map-Register message format is:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=3 |P|S|R| Reserved |E|T|a|R|M| Record Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . . . Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Key ID | Algorithm ID | Authentication Data Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Authentication Data ~
+-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Record TTL |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
R | Locator Count | EID mask-len | ACT |A| Reserved |
e +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
c | Rsvd | Map-Version Number | EID-Prefix-AFI |
o +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
r | EID-Prefix |
d +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| /| Priority | Weight | M Priority | M Weight |
| L +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| o | Unused Flags |L|p|R| Loc-AFI |
| c +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| \| Locator |
+-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Packet field descriptions:
Type: 3 (Map-Register)
P: This is the proxy Map-Reply bit. When set to 1, an ETR sends a
Map-Register message requesting the Map-Server to proxy a Map-
Reply. The Map-Server will send non-authoritative Map-Replies on
behalf of the ETR.
S: This is the security-capable bit. When set, the procedures from
[I-D.ietf-lisp-sec] are supported.
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Reserved: This field MUST be set to 0 on transmit and MUST be
ignored on receipt.
E: This is the Map-Register EID-notify bit. This is used by a First-
Hop-Router (FHR) which discovers a dynamic-EID. This EID-notify
based Map-Register is sent by the FHR to the same site xTR that
propogates the Map-Register to the mapping system. The site xTR
keeps state to later Map-Notify the FHR after the EID has moves
away. See [I-D.ietf-lisp-eid-mobility] for a detailed use-case.
T: This is the use-TTL for timeout bit. When set to 1, the xTR wants
the Map-Server to time out registrations based on the value in the
"Record TTL" field of this message. Otherwise, the default
timeout described in Section 8.2 is used.
a: This is the merge-request bit. When set to 1, the xTR requests to
merge RLOC-records from different xTRs registering the same EID-
record. See signal-free multicast [RFC8378] for one use case
example.
R: This reserved bit MUST be set to 0 on transmit and MUST be ignored
on receipt.
M: This is the want-map-notify bit. When set to 1, an ETR is
requesting a Map-Notify message to be returned in response to
sending a Map-Register message. The Map-Notify message sent by a
Map-Server is used to acknowledge receipt of a Map-Register
message.
Record Count: This is the number of records in this Map-Register
message. A record is comprised of that portion of the packet
labeled 'Record' above and occurs the number of times equal to
Record Count.
Nonce: This 8-octet 'Nonce' field is incremented each time a Map-
Register message is sent. When a Map-Register acknowledgement is
requested, the nonce is returned by Map-Servers in Map-Notify
messages. Since the entire Map-Register message is authenticated,
the 'Nonce' field serves to protect against Map-Register replay
attacks.
Key ID: This is a configured key-id value that corresponds to a
shared-secret password that is used to authenticate the sender.
Multiple shared-secrets can be used to roll over keys in a non-
disruptive way.
Algorithm ID: This is the configured Message Authentication Code
(MAC) algorithm value used for the authentication function. See
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Algorithm ID Numbers in the Section 12.5 for codepoint
assignments.
Authentication Data Length: This is the length in octets of the
'Authentication Data' field that follows this field. The length
of the 'Authentication Data' field is dependent on the MAC
algorithm used. The length field allows a device that doesn't
know the MAC algorithm to correctly parse the packet.
Authentication Data: This is the output of the MAC algorithm. The
entire Map-Register payload (from and including the LISP message
type field through the end of the last RLOC record) is
authenticated with this field preset to 0. After the MAC is
computed, it is placed in this field. Implementations of this
specification MUST include support for either HMAC-SHA-1-96
[RFC2404] and HMAC-SHA-256-128 [RFC4868] where the latter is
RECOMMENDED.
The definition of the rest of the Map-Register can be found in EID-
record description in Section 5.4.
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5.7. Map-Notify/Map-Notify-Ack Message Format
This section specifies the encoding format for the Map-Notify and
Map-Notify-Ack messages. The messages are sent inside a UDP packet
with source and destination UDP ports equal to 4342.
The Map-Notify and Map-Notify-Ack message formats are:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=4/5| Reserved | Record Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . . . Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Key ID | Algorithm ID | Authentication Data Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Authentication Data ~
+-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Record TTL |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
R | Locator Count | EID mask-len | ACT |A| Reserved |
e +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
c | Rsvd | Map-Version Number | EID-Prefix-AFI |
o +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
r | EID-Prefix |
d +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| /| Priority | Weight | M Priority | M Weight |
| L +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| o | Unused Flags |L|p|R| Loc-AFI |
| c +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| \| Locator |
+-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Packet field descriptions:
Type: 4/5 (Map-Notify/Map-Notify-Ack)
The Map-Notify message has the same contents as a Map-Register
message. See the Map-Register section for field descriptions.
The Map-Notify-Ack message has the same contents as a Map-Notify
message. It is used to acknowledge the receipt of a Map-Notify and
for the sender to stop retransmitting a Map-Notify with the same
nonce.
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A Map-Server sends an unsolicited Map-Notify message (one that is not
used as an acknowledgment to a Map-Register message) that follows the
Congestion Control And Relability Guideline sections of [RFC8085]. A
Map-Notify is retransmitted until a Map-Notify-Ack is received by the
Map-Server with the same nonce used in the Map-Notify message. If a
Map-Notify-Ack is never received by the Map-Server, it issues a log
message. An implementation SHOULD retransmit up to 3 times at 3
second retransmission intervals, after which time the retransmission
interval is exponentially backed-off for another 3 retransmission
attempts. After this time, an xTR can only get the RLOC-set change
by later querying the mapping system or by RLOC-probing one of the
RLOCs of the existing cached RLOC-set to get the new RLOC-set.
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5.8. Encapsulated Control Message Format
An Encapsulated Control Message (ECM) is used to encapsulate control
packets sent between xTRs and the mapping database system.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | IPv4 or IPv6 Header |
OH | (uses RLOC addresses) |
\ | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port = xxxx | Dest Port = 4342 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
LISP |Type=8 |S|D|E|M| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | IPv4 or IPv6 Header |
IH | (uses RLOC or EID addresses) |
\ | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port = xxxx | Dest Port = yyyy |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
LCM | LISP Control Message |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Packet header descriptions:
OH: The outer IPv4 or IPv6 header, which uses RLOC addresses in the
source and destination header address fields.
UDP: The outer UDP header with destination port 4342. The source
port is randomly allocated. The checksum field MUST be non-
zero.
LISP: Type 8 is defined to be a "LISP Encapsulated Control Message",
and what follows is either an IPv4 or IPv6 header as encoded by
the first 4 bits after the 'Reserved' field.
Type: 8 (Encapsulated Control Message (ECM))
S: This is the Security bit. When set to 1, the field following
the 'Reserved' field will have the following Authentication
Data format and follow the procedures from [I-D.ietf-lisp-sec].
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AD Type | Authentication Data Content . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
D: This is the DDT-bit. When set to 1, the sender is requesting a
Map-Referral message to be returned. The details of this
procedure are described in [RFC8111].
E: This is the to-ETR bit. When set to 1, the Map-Server's
intention is to forward the ECM to an authoritative ETR.
M: This is the to-MS bit. When set to 1, a Map-Request is being
sent to a co-located Map-Resolver and Map-Server where the
message can be processed directly by the Map-Server versus the
Map-Resolver using the LISP-DDT procedures in [RFC8111].
IH: The inner IPv4 or IPv6 header, which can use either RLOC or EID
addresses in the header address fields. When a Map-Request is
encapsulated in this packet format, the destination address in
this header is an EID.
UDP: The inner UDP header, where the port assignments depend on the
control packet being encapsulated. When the control packet is
a Map-Request or Map-Register, the source port is selected by
the ITR/PITR and the destination port is 4342. When the
control packet is a Map-Reply, the source port is 4342 and the
destination port is assigned from the source port of the
invoking Map-Request. Port number 4341 MUST NOT be assigned to
either port. The checksum field MUST be non-zero.
LCM: The format is one of the control message formats described in
this section. Map-Request messages are allowed to be Control-
Plane (ECM) encapsulated. When Map-Requests are sent for RLOC-
Probing purposes (i.e. the probe-bit is set), they MUST NOT be
sent inside Encapsulated Control Messages. PIM Join/Prune
messages [RFC6831] are also allowed to be Control-Plane (ECM)
encapsulated.
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6. Changing the Contents of EID-to-RLOC Mappings
In the LISP architecture ITRs/PITRs use a local Map-Cache to store
EID-to-RLOC mappings for forwarding. When an ETR updates a mapping a
mechanism is required to inform ITRs/PITRs that are using such
mappings.
The LISP Data-Plane defines several mechanism to update mappings
[I-D.ietf-lisp-rfc6830bis]. This document specifies the Solicit-Map
Request (SMR), a Control-Plane push-based mechanism. An additional
Control-Plane mechanism based on the Publish/subscribe paradigm is
specified in [I-D.ietf-lisp-pubsub].
6.1. Solicit-Map-Request (SMR)
Soliciting a Map-Request is a selective way for ETRs, at the site
where mappings change, to control the rate they receive requests for
Map-Reply messages. SMRs are also used to tell remote ITRs to update
the mappings they have cached.
Since ETRs are not required to keep track of remote ITRs that have
cached their mappings, they do not know which ITRs need to have their
mappings updated. As a result, an ETR will solicit Map-Requests
(called an SMR message) to those sites to which it has been sending
LISP encapsulated data packets for the last minute. In particular,
an ETR will send an SMR to an ITR to which it has recently sent
encapsulated data. This can only occur when both ITR and ETR
functionality reside in the same router.
An SMR message is simply a bit set in a Map-Request message. An ITR
or PITR will send a Map-Request when they receive an SMR message.
Both the SMR sender and the Map-Request responder MUST rate-limit
these messages. Rate-limiting can be implemented as a global rate-
limiter or one rate-limiter per SMR destination.
The following procedure shows how an SMR exchange occurs when a site
is doing Locator-Set compaction for an EID-to-RLOC mapping:
1. When the database mappings in an ETR change, the ETRs at the site
begin to send Map-Requests with the SMR bit set for each Locator
in each Map-Cache entry the ETR (when it is an xTR co-located as
an ITR) caches.
2. A remote ITR that receives the SMR message will schedule sending
a Map-Request message to the source locator address of the SMR
message or to the mapping database system. A newly allocated
random nonce is selected, and the EID-Prefix used is the one
copied from the SMR message. If the source Locator is the only
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Locator in the cached Locator-Set, the remote ITR SHOULD send a
Map-Request to the database mapping system just in case the
single Locator has changed and may no longer be reachable to
accept the Map-Request.
3. The remote ITR MUST rate-limit the Map-Request until it gets a
Map-Reply while continuing to use the cached mapping. When
Map-Versioning as described in [I-D.ietf-lisp-6834bis] is used,
an SMR sender can detect if an ITR is using the most up-to-date
database mapping.
4. The site sending SMR messages will reply to the Map-Request with
a Map-Reply message that has a nonce from the SMR-invoked Map-
Request. The Map-Reply messages MUST be rate-limited according
to procedures in [RFC8085]. This is important to avoid Map-Reply
implosion.
5. The ETRs at the site with the changed mapping record the fact
that the site that sent the Map-Request has received the new
mapping data in the Map-Cache entry for the remote site so the
Locator-Status-Bits are reflective of the new mapping for packets
going to the remote site. The ETR then stops sending SMR
messages.
For security reasons, an ITR MUST NOT process unsolicited Map-
Replies. To avoid Map-Cache entry corruption by a third party, a
sender of an SMR-based Map-Request MUST be verified. If an ITR
receives an SMR-based Map-Request and the source is not in the
Locator-Set for the stored Map-Cache entry, then the responding Map-
Request MUST be sent with an EID destination to the mapping database
system. Since the mapping database system is a more secure way to
reach an authoritative ETR, it will deliver the Map-Request to the
authoritative source of the mapping data.
When an ITR receives an SMR-based Map-Request for which it does not
have a cached mapping for the EID in the SMR message, it SHOULD NOT
send an SMR-invoked Map-Request. This scenario can occur when an ETR
sends SMR messages to all Locators in the Locator-Set it has stored
in its Map-Cache but the remote ITRs that receive the SMR may not be
sending packets to the site. There is no point in updating the ITRs
until they need to send, in which case they will send Map-Requests to
obtain a Map-Cache entry.
7. Routing Locator Reachability
This document defines several Control-Plane mechanisms for
determining RLOC reachability. Please note that additional Data-
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Plane reachability mechanisms are defined in
[I-D.ietf-lisp-rfc6830bis].
1. An ITR may receive an ICMP Network Unreachable or Host
Unreachable message for an RLOC it is using. This indicates that
the RLOC is likely down. Note that trusting ICMP messages may
not be desirable, but neither is ignoring them completely.
Implementations are encouraged to follow current best practices
in treating these conditions [I-D.ietf-opsec-icmp-filtering].
2. When an ITR participates in the routing protocol that operates in
the underlay routing system, it can determine that an RLOC is
down when no Routing Information Base (RIB) entry exists that
matches the RLOC IP address.
3. An ITR may receive an ICMP Port Unreachable message from a
destination host. This occurs if an ITR attempts to use
interworking [RFC6832] and LISP-encapsulated data is sent to a
non-LISP-capable site.
4. An ITR may receive a Map-Reply from an ETR in response to a
previously sent Map-Request. The RLOC source of the Map-Reply is
likely up, since the ETR was able to send the Map-Reply to the
ITR.
5. An ITR/ETR pair can use the 'RLOC-Probing' mechanism described
below.
When ITRs receive ICMP Network Unreachable or Host Unreachable
messages as a method to determine unreachability, they will refrain
from using Locators that are described in Locator lists of Map-
Replies. However, using this approach is unreliable because many
network operators turn off generation of ICMP Destination Unreachable
messages.
If an ITR does receive an ICMP Network Unreachable or Host
Unreachable message, it MAY originate its own ICMP Destination
Unreachable message destined for the host that originated the data
packet the ITR encapsulated.
Also, BGP-enabled ITRs can unilaterally examine the RIB to see if a
locator address from a Locator-Set in a mapping entry matches a
prefix. If it does not find one and BGP is running in the Default-
Free Zone (DFZ), it can decide to not use the Locator even though the
Locator-Status-Bits indicate that the Locator is up. In this case,
the path from the ITR to the ETR that is assigned the Locator is not
available. More details are in [I-D.meyer-loc-id-implications].
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Optionally, an ITR can send a Map-Request to a Locator, and if a Map-
Reply is returned, reachability of the Locator has been determined.
Obviously, sending such probes increases the number of control
messages originated by Tunnel Routers for active flows, so Locators
are assumed to be reachable when they are advertised.
This assumption does create a dependency: Locator unreachability is
detected by the receipt of ICMP Host Unreachable messages. When a
Locator has been determined to be unreachable, it is not used for
active traffic; this is the same as if it were listed in a Map-Reply
with Priority 255.
The ITR can test the reachability of the unreachable Locator by
sending periodic Requests. Both Requests and Replies MUST be rate-
limited. Locator reachability testing is never done with data
packets, since that increases the risk of packet loss for end-to-end
sessions.
7.1. RLOC-Probing Algorithm
RLOC-Probing is a method that an ITR or PITR can use to determine the
reachability status of one or more Locators that it has cached in a
Map-Cache entry. The probe-bit of the Map-Request and Map-Reply
messages is used for RLOC-Probing.
RLOC-Probing is done in the control plane on a timer basis, where an
ITR or PITR will originate a Map-Request destined to a locator
address from one of its own locator addresses. A Map-Request used as
an RLOC-probe is NOT encapsulated and NOT sent to a Map-Server or to
the mapping database system as one would when soliciting mapping
data. The EID record encoded in the Map-Request is the EID-Prefix of
the Map-Cache entry cached by the ITR or PITR. The ITR MAY include a
mapping data record for its own database mapping information that
contains the local EID-Prefixes and RLOCs for its site. RLOC-probes
are sent periodically using a jittered timer interval.
When an ETR receives a Map-Request message with the probe-bit set, it
returns a Map-Reply with the probe-bit set. The source address of
the Map-Reply is set to the IP address of the outgoing interface the
Map-Reply destination address routes to. The Map-Reply SHOULD
contain mapping data for the EID-Prefix contained in the Map-Request.
This provides the opportunity for the ITR or PITR that sent the RLOC-
probe to get mapping updates if there were changes to the ETR's
database mapping entries.
There are advantages and disadvantages of RLOC-Probing. The main
benefit of RLOC-Probing is that it can handle many failure scenarios
allowing the ITR to determine when the path to a specific Locator is
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reachable or has become unreachable, thus providing a robust
mechanism for switching to using another Locator from the cached
Locator. RLOC-Probing can also provide rough Round-Trip Time (RTT)
estimates between a pair of Locators, which can be useful for network
management purposes as well as for selecting low delay paths. The
major disadvantage of RLOC-Probing is in the number of control
messages required and the amount of bandwidth used to obtain those
benefits, especially if the requirement for failure detection times
is very small.
8. Interactions with Other LISP Components
8.1. ITR EID-to-RLOC Mapping Resolution
An ITR is configured with one or more Map-Resolver addresses. These
addresses are "Locators" (or RLOCs) and MUST be routable on the
underlying core network; they MUST NOT need to be resolved through
LISP EID-to-RLOC mapping, as that would introduce a circular
dependency. When using a Map-Resolver, an ITR does not need to
connect to any other database mapping system. In particular, the ITR
need not connect to the LISP-ALT infrastructure or implement the BGP
and GRE protocols that it uses.
An ITR sends an Encapsulated Map-Request to a configured Map-Resolver
when it needs an EID-to-RLOC mapping that is not found in its local
Map-Cache. Using the Map-Resolver greatly reduces both the
complexity of the ITR implementation and the costs associated with
its operation.
In response to an Encapsulated Map-Request, the ITR can expect one of
the following:
o An immediate Negative Map-Reply (with action code of "Natively-
Forward", 15-minute Time to Live (TTL)) from the Map-Resolver if
the Map-Resolver can determine that the requested EID does not
exist. The ITR saves the EID-Prefix returned in the Map-Reply in
its cache, marks it as non-LISP-capable, and knows not to attempt
LISP encapsulation for destinations matching it.
o A Negative Map-Reply, with action code of "Natively-Forward", from
a Map-Server that is authoritative for an EID-Prefix that matches
the requested EID but that does not have an actively registered,
more-specific ID-prefix. In this case, the requested EID is said
to match a "hole" in the authoritative EID-Prefix. If the
requested EID matches a more-specific EID-Prefix that has been
delegated by the Map-Server but for which no ETRs are currently
registered, a 1-minute TTL is returned. If the requested EID
matches a non-delegated part of the authoritative EID-Prefix, then
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it is not a LISP EID and a 15-minute TTL is returned. See
Section 8.2 for discussion of aggregate EID-Prefixes and details
of Map-Server EID-Prefix matching.
o A LISP Map-Reply from the ETR that owns the EID-to-RLOC mapping or
possibly from a Map-Server answering on behalf of the ETR. See
Section 8.4 for more details on Map-Resolver message processing.
Note that an ITR may be configured to both use a Map-Resolver and to
participate in a LISP-ALT logical network. In such a situation, the
ITR SHOULD send Map-Requests through the ALT network for any EID-
Prefix learned via ALT BGP. Such a configuration is expected to be
very rare, since there is little benefit to using a Map-Resolver if
an ITR is already using LISP-ALT. There would be, for example, no
need for such an ITR to send a Map-Request to a possibly non-existent
EID (and rely on Negative Map-Replies) if it can consult the ALT
database to verify that an EID-Prefix is present before sending that
Map-Request.
8.2. EID-Prefix Configuration and ETR Registration
An ETR publishes its EID-Prefixes on a Map-Server by sending LISP
Map-Register messages. A Map-Register message includes
authentication data, so prior to sending a Map-Register message, the
ETR and Map-Server SHOULD be configured with a shared secret or other
relevant authentication information. A Map-Server's configuration
SHOULD also include a list of the EID-Prefixes for which each ETR is
authoritative. Upon receipt of a Map-Register from an ETR, a Map-
Server accepts only EID-Prefixes that are configured for that ETR.
Failure to implement such a check would leave the mapping system
vulnerable to trivial EID-Prefix hijacking attacks. As developers
and operators gain experience with the mapping system, additional,
stronger security measures may be added to the registration process.
In addition to the set of EID-Prefixes defined for each ETR that may
register, a Map-Server is typically also configured with one or more
aggregate prefixes that define the part of the EID numbering space
assigned to it. When LISP-ALT is the database in use, aggregate EID-
Prefixes are implemented as discard routes and advertised into ALT
BGP. The existence of aggregate EID-Prefixes in a Map-Server's
database means that it may receive Map Requests for EID-Prefixes that
match an aggregate but do not match a registered prefix; Section 8.3
describes how this is handled.
Map-Register messages are sent periodically from an ETR to a Map-
Server with a suggested interval between messages of one minute. A
Map-Server SHOULD time out and remove an ETR's registration if it has
not received a valid Map-Register message within the past
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three minutes. When first contacting a Map-Server after restart or
changes to its EID-to-RLOC database mappings, an ETR MAY initially
send Map-Register messages at an increased frequency, up to one every
20 seconds. This "quick registration" period is limited to
five minutes in duration.
An ETR MAY request that a Map-Server explicitly acknowledge receipt
and processing of a Map-Register message by setting the "want-map-
notify" (M-bit) flag. A Map-Server that receives a Map-Register with
this flag set will respond with a Map-Notify message. Typical use of
this flag by an ETR would be to set it for Map-Register messages sent
during the initial "quick registration" with a Map-Server but then
set it only occasionally during steady-state maintenance of its
association with that Map-Server. Note that the Map-Notify message
is sent to UDP destination port 4342, not to the source port
specified in the original Map-Register message.
Note that a one-minute minimum registration interval during
maintenance of an ETR-Map-Server association places a lower bound on
how quickly and how frequently a mapping database entry can be
updated. This may have implications for what sorts of mobility can
be supported directly by the mapping system; shorter registration
intervals or other mechanisms might be needed to support faster
mobility in some cases. For a discussion on one way that faster
mobility may be implemented for individual devices, please see
[I-D.ietf-lisp-mn].
An ETR MAY also request, by setting the "proxy Map-Reply" flag
(P-bit) in the Map-Register message, that a Map-Server answer Map-
Requests instead of forwarding them to the ETR. See Section 7.1 for
details on how the Map-Server sets certain flags (such as those
indicating whether the message is authoritative and how returned
Locators SHOULD be treated) when sending a Map-Reply on behalf of an
ETR. When an ETR requests proxy reply service, it SHOULD include all
RLOCs for all ETRs for the EID-Prefix being registered, along with
the routable flag ("R-bit") setting for each RLOC. The Map-Server
includes all of this information in Map-Reply messages that it sends
on behalf of the ETR. This differs from a non-proxy registration,
since the latter need only provide one or more RLOCs for a Map-Server
to use for forwarding Map-Requests; the registration information is
not used in Map-Replies, so it being incomplete is not incorrect.
An ETR that uses a Map-Server to publish its EID-to-RLOC mappings
does not need to participate further in the mapping database
protocol(s). When using a LISP-ALT mapping database, for example,
this means that the ETR does not need to implement GRE or BGP, which
greatly simplifies its configuration and reduces its cost of
operation.
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Note that use of a Map-Server does not preclude an ETR from also
connecting to the mapping database (i.e., it could also connect to
the LISP-ALT network), but doing so doesn't seem particularly useful,
as the whole purpose of using a Map-Server is to avoid the complexity
of the mapping database protocols.
8.3. Map-Server Processing
Once a Map-Server has EID-Prefixes registered by its client ETRs, it
can accept and process Map-Requests for them.
In response to a Map-Request (received over the ALT if LISP-ALT is in
use), the Map-Server first checks to see if the destination EID
matches a configured EID-Prefix. If there is no match, the Map-
Server returns a Negative Map-Reply with action code "Natively-
Forward" and a 15-minute TTL. This can occur if a Map Request is
received for a configured aggregate EID-Prefix for which no more-
specific EID-Prefix exists; it indicates the presence of a non-LISP
"hole" in the aggregate EID-Prefix.
Next, the Map-Server checks to see if any ETRs have registered the
matching EID-Prefix. If none are found, then the Map-Server returns
a Negative Map-Reply with action code "Natively-Forward" and a
1-minute TTL.
If the EID-prefix is either registered or not registered to the
mapping system and there is a policy in the Map-Server to have the
requestor drop packets for the matching EID-prefix, then a Drop/
Policy-Denied action is returned. If the EID-prefix is registered or
not registered and there is a authentication failure, then a Drop/
Authentication- failure action is returned. If either of these
actions result as a temporary state in policy or authentication then
a Send-Map-Request action with 1-minute TTL MAY be returned to allow
the requestor to retry the Map-Request.
If any of the registered ETRs for the EID-Prefix have requested proxy
reply service, then the Map-Server answers the request instead of
forwarding it. It returns a Map-Reply with the EID-Prefix, RLOCs,
and other information learned through the registration process.
If none of the ETRs have requested proxy reply service, then the Map-
Server re-encapsulates and forwards the resulting Encapsulated Map-
Request to one of the registered ETRs. It does not otherwise alter
the Map-Request, so any Map-Reply sent by the ETR is returned to the
RLOC in the Map-Request, not to the Map-Server. Unless also acting
as a Map-Resolver, a Map-Server should never receive Map-Replies; any
such messages SHOULD be discarded without response, perhaps
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accompanied by the logging of a diagnostic message if the rate of
Map-Replies is suggestive of malicious traffic.
8.4. Map-Resolver Processing
Upon receipt of an Encapsulated Map-Request, a Map-Resolver
decapsulates the enclosed message and then searches for the requested
EID in its local database of mapping entries (statically configured
or learned from associated ETRs if the Map-Resolver is also a Map-
Server offering proxy reply service). If it finds a matching entry,
it returns a LISP Map-Reply with the known mapping.
If the Map-Resolver does not have the mapping entry and if it can
determine that the EID is not in the mapping database (for example,
if LISP-ALT is used, the Map-Resolver will have an ALT forwarding
table that covers the full EID space), it immediately returns a
negative LISP Map-Reply, with action code "Natively-Forward" and a
15-minute TTL. To minimize the number of negative cache entries
needed by an ITR, the Map-Resolver SHOULD return the least-specific
prefix that both matches the original query and does not match any
EID-Prefix known to exist in the LISP-capable infrastructure.
If the Map-Resolver does not have sufficient information to know
whether the EID exists, it needs to forward the Map-Request to
another device that has more information about the EID being
requested. To do this, it forwards the unencapsulated Map-Request,
with the original ITR RLOC as the source, to the mapping database
system. Using LISP-ALT, the Map-Resolver is connected to the ALT
network and sends the Map-Request to the next ALT hop learned from
its ALT BGP neighbors. The Map-Resolver does not send any response
to the ITR; since the source RLOC is that of the ITR, the ETR or Map-
Server that receives the Map-Request over the ALT and responds will
do so directly to the ITR.
8.4.1. Anycast Operation
A Map-Resolver can be set up to use "anycast", where the same address
is assigned to multiple Map-Resolvers and is propagated through IGP
routing, to facilitate the use of a topologically close Map-Resolver
by each ITR.
ETRs MAY have anycast RLOC addresses which are registered as part of
their RLOC-set to the mapping system. However, registrations MUST
use their unique RLOC addresses or distinct authentication keys to
identify security associations with the Map-Servers.
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9. Security Considerations
A complete LISP threat analysis can be found in [RFC7835]. In what
follows we highlight security considerations that apply when LISP is
deployed in environments such as those specified in Section 1.1,
where the following assumptions hold:
1. The Mapping System is secure and trusted, and for the purpose of
this security considerations the Mapping System is considered as
one trusted element.
2. The ETRs have a pre-configured trust relationship with the
Mapping System, which includes some form of shared keys, and the
Mapping System is aware of which EIDs an ETR can advertise. How
those keys and mappings gets established is out of the scope of
this document.
3. LISP-SEC [I-D.ietf-lisp-sec] MUST be implemented. Network
operartors should carefully weight how the LISP-SEC threat model
applies to their particular use case or deployment. If they
decide to ignore a particular recommendation, they should make
sure the risk associated with the corresponding threats is well
understood.
The Map-Request/Map-Reply message exchange can be exploited by an
attacker to mount DoS and/or amplification attacks. Attackers can
send Map-Requests at high rates to overload LISP nodes and increase
the state maintained by such nodes or consume CPU cycles. Such
threats can be mitigated by systematically applying filters and rate
limiters.
The 2-way LISP control-plane header nonce exchange can be used to
avoid ITR spoofing attacks, but active on-path attackers (e.g 'man-
in-the-middle') capable of intercepting the nonce can exploit the
Map-Request/Map-Reply message exchange to inject forged mappings
directly in the ITR EID-to-RLOC map-cache. In addition, valid ETRs
in the system can perform overclaiming attacks. In this case,
attackers can claim to own an EID-prefix that is larger than the
prefix owned by the ETR. Such attacks can be addressed by using
LISP-SEC [I-D.ietf-lisp-sec]. The LISP-SEC protocol defines a
mechanism for providing origin authentication, integrity, anti-
replay, protection, and prevention of 'man-in-the-middle' and 'prefix
overclaiming' attacks on the Map-Request/Map-Reply exchange. In
addition and while beyond the scope of securing an individual Map-
Server or Map-Resolver, it should be noted that LISP-SEC can be
complemented by additional security mechanisms defined by the Mapping
System Infrastructure. For instance, BGP-based LISP-ALT [RFC6836]
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can take advantage of standards work on adding security to BGP while
LISP-DDT [RFC8111] defines its own additional security mechanisms.
To publish an authoritative EID-to-RLOC mapping with a Map-Server
using the Map-Register message, an ETR includes authentication data
that is a MAC of the entire message using a pair-wise shared key. An
implementation MUST support use of HMAC-SHA-1-96 [RFC2104] and SHOULD
support use of HMAC-SHA-256-128 [RFC6234] (SHA-256 truncated to 128
bits). The Map-Register message is vulnerable to replay attacks by a
man-in-the-middle. Deployments that are concerned with active man-
in-the-middle attacks to the Map-Register message SHOULD use a
transport-level integrity and anti-reply protection mechanism such as
IPSEC [RFC6071]. In addition, a compromised ETR can overclaim the
prefix it owns and successfully register it on its corresponding Map-
Server. To mitigate this and as noted in Section 8.2, a Map-Server
SHOULD verify that all EID-Prefixes registered by an ETR match the
configuration stored on the Map-Server.
A complete LISP threat analysis has been published in [RFC7835].
Please refer to it for more detailed security related details.
10. Privacy Considerations
As noted by [RFC6973] privacy is a complex issue that greatly depends
on the specific protocol use-case and deployment. As noted in
section 1.1 of [I-D.ietf-lisp-rfc6830bis] LISP focuses on use-cases
where entities communicate over the public Internet while keeping
separate addressing and topology. In what follows we detail the
privacy threats introduced by the LISP Control Plane, the analysis is
based on the guidelines detailed in [RFC6973].
LISP can use long-lived identifiers (EIDs) that survive mobility
events. Such identifiers bind to the RLOCs of the nodes, which
represents the topological location with respect to the specific LISP
deployments. In addition, EID-to-RLOC mappings are typically
considered public information within the LISP deployment when
control-plane messages are not encrypted, and can be eavesdropped
while Map-Request messages are sent to the corresponding Map-
Resolvers or Map-Register messages to Map-Servers.
In this context, attackers can correlate the EID with the RLOC and
track the corresponding user topological location and/or mobility.
This can be achieved by off-path attackers, if they are
authenticated, by querying the mapping system. Deployments concerned
about this threat can use access control-lists or stronger
authentication mechanisms [I-D.ietf-lisp-ecdsa-auth] in the mapping
system to make sure that only authorized users can access this
information (data minimization). Use of ephemeral EIDs
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[I-D.ietf-lisp-eid-anonymity] to achieve anonymity is another
mechanism to lessen persistency and identity tracking.
11. Changes since RFC 6833
For implementation considerations, the following changes have been
made to this document since RFC 6833 was published:
o A Map-Notify-Ack message is added in this document to provide
reliability for Map-Notify messages. Any receiver of a Map-Notify
message must respond with a Map-Notify-Ack message. Map-Servers
who are senders of Map-Notify messages, must queue the Map-Notify
contents until they receive a Map-Notify-Ack with the nonce used
in the Map-Notify message. Note that implementations for Map-
Notify-Ack support already exist and predate this document.
o This document is incorporating the codepoint for the Map-Referral
message from the LISP-DDT specification [RFC8111] to indicate that
a Map-Server must send the final Map-Referral message when it
participates in the LISP-DDT mapping system procedures.
o The "m", "I", "L", and "D" bits are added to the Map-Request
message. See Section 5.3 for details.
o The "S", "I", "E", "T", "a", and "m" bits are added to the Map-
Register message. See Section 5.6 for details.
o The 16-bit Key-ID field of the Map-Register message has been split
into a 8-bit Key-ID field and a 8-bit Algorithm-ID field.
o This document adds two new Action values that are in an EID-record
that appear in Map-Reply, Map-Register, Map-Notify, and Map-
Notify-Ack messages. The Drop/Policy-Denied and Drop/Auth-Failure
are the descriptions for the two new action values. See
Section 5.4 for details.
12. IANA Considerations
This section provides guidance to the Internet Assigned Numbers
Authority (IANA) regarding registration of values related to this
LISP Control-Plane specification, in accordance with BCP 26
[RFC8126].
There are three namespaces (listed in the sub-sections below) in LISP
that have been registered.
o LISP IANA registry allocations should not be made for purposes
unrelated to LISP routing or transport protocols.
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o The following policies are used here with the meanings defined in
BCP 26: "Specification Required", "IETF Review", "Experimental
Use", and "First Come First Served".
12.1. LISP UDP Port Numbers
The IANA registry has allocated UDP port number 4342 for the LISP
Control-Plane. IANA has updated the description for UDP port 4342 as
follows:
Keyword Port Transport Layer Description
------- ---- --------------- -----------
lisp-control 4342 udp LISP Control Packets
12.2. LISP Packet Type Codes
It is being requested that the IANA be authoritative for LISP Packet
Type definitions and it is requested to replace the [RFC6830]
registry message references with the RFC number assigned to this
document.
Based on deployment experience of [RFC6830], the Map-Notify-Ack
message, message type 5, was added by this document. This document
requests IANA to add it to the LISP Packet Type Registry.
Name Number Defined in
---- ------ -----------
LISP Map-Notify-Ack 5 RFC6833bis
12.3. LISP ACT and Flag Fields
New ACT values can be allocated through IETF review or IESG approval.
Four values have already been allocated by [RFC6830], IANA is
requested to replace the [RFC6830] reference for this registry with
the RFC number assigned to this document and the [RFC6830]. Action
values references with the RFC number assigned to this document.
This specification changes the name of ACT type 3 value from "Drop"
to "Drop/No-Reason" as well as adding two new ACT values, the "Drop/
Policy-Denied" (type 4) and "Drop/Authentication-Failure" (type 5).
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Value Action Description Reference
----- ------ ----------- ---------
4 Drop/ A Packet matching this Map-Cache RFC6833bis
Policy-Denied entry is dropped because the target
EID is policy-denied by the xTR or
the mapping system.
5 Drop/ A Packet matching this Map-Cache RFC6833bis
Auth-Failure entry is dropped because the
Map-Request for target EID fails an
authentication check by the xTR or
the mapping system.
In addition, LISP has a number of flag fields and reserved fields,
such as the LISP header flags field [I-D.ietf-lisp-rfc6830bis]. New
bits for flags in these fields can be implemented after IETF review
or IESG approval, but these need not be managed by IANA.
12.4. LISP Address Type Codes
LISP Canonical Address Format (LCAF) [RFC8060] is an 8-bit field that
defines LISP-specific encodings for AFI value 16387. LCAF encodings
are used for specific use-cases where different address types for
EID-records and RLOC-records are required.
The IANA registry "LISP Canonical Address Format (LCAF) Types" is
used for LCAF types. The registry for LCAF types use the
Specification Required policy [RFC8126]. Initial values for the
registry as well as further information can be found in [RFC8060].
Therefore, there is no longer a need for the "LISP Address Type
Codes" registry requested by [RFC6830]. This document requests to
remove it.
12.5. LISP Algorithm ID Numbers
In [RFC6830], a request for a "LISP Key ID Numbers" registry was
submitted. This document renames the registry to "LISP Algorithm ID
Numbers" and requests the IANA to make the name change.
The following Algorithm ID values are defined by this specification
as used in any packet type that references a 'Algorithm ID' field:
Name Number Defined in
-----------------------------------------------
None 0 RFC6833bis
HMAC-SHA-1-96 1 [RFC2404]
HMAC-SHA-256-128 2 [RFC4868]
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Number values are in the range of 0 to 255. The allocation of values
is on a first come first served basis.
12.6. LISP Bit Flags
This document asks IANA to create a registry for allocation of bits
in several headers of the LISP control plane, namely in the Map-
Request, Map-Reply, Map-Register, Encapsulated Control Message (ECM)
messages. Bit allocations are also requested for EID-records and
RLOC-records. The registry created should be named "LISP Control
Plane Header Bits". A sub-registry needs to be created per each
message and record. The name of each sub-registry is indicated
below, along with its format and allocation of bits defined in this
document. Any additional bits allocation, requires a specification,
according with [RFC5226] policies.
Sub-Registry: Map-Request Header Bits [Section 5.2]:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=1 |A|M|P|S|p|s|R|R| Rsvd |L|D| IRC | Record Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+----------+---------------+------------+---------------------------+
| Spec | IANA Name | Bit | Description |
| Name | | Position | |
+----------+---------------+------------+---------------------------+
| A | map-request-A | 4 | Authoritative Bit |
| M | map-request-M | 5 | Map Data Present Bit |
| P | map-request-P | 6 | RLOC-Probe Request Bit |
| S | map-request-S | 7 | Solicit Map-Request (SMR) |
| | | | Bit |
| p | map-request-p | 8 | Proxy-ITR Bit |
| s | map-request-s | 9 | Solicit Map-Request |
| | | | Invoked Bit |
| L | map-request-L | 17 | Local xTR Bit |
| D | map-request-D | 18 | Don't Map-Reply Bit |
+----------+---------------+------------+---------------------------+
LISP Map-Request Header Bits
Sub-Registry: Map-Reply Header Bits [Section 5.4]:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=2 |P|E|S| Reserved | Record Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-----------+-------------+--------------+------------------------+
| Spec Name | IANA Name | Bit Position | Description |
+-----------+-------------+--------------+------------------------+
| P | map-reply-P | 4 | RLOC-Probe Bit |
| E | map-reply-E | 5 | Echo Nonce Capable Bit |
| S | map-reply-S | 6 | Security Bit |
+-----------+-------------+--------------+------------------------+
LISP Map-Reply Header Bits
Sub-Registry: Map-Register Header Bits [Section 5.6]:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=3 |P|S|R| Reserved |E|T|a|R|M| Record Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-----------+----------------+--------------+----------------------+
| Spec Name | IANA Name | Bit Position | Description |
+-----------+----------------+--------------+----------------------+
| P | map-register-P | 4 | Proxy Map-Reply Bit |
| S | map-register-S | 5 | LISP-SEC Capable Bit |
+-----------+----------------+--------------+----------------------+
LISP Map-Register Header Bits
Sub-Registry: Encapsulated Control Message (ECM) Header Bits
[Section 5.8]:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=8 |S|D|E|M| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+-----------+-----------+--------------+----------------------------+
| Spec Name | IANA Name | Bit Position | Description |
+-----------+-----------+--------------+----------------------------+
| S | ecm-S | 4 | Security Bit |
| D | ecm-D | 5 | LISP-DDT Bit |
| E | ecm-E | 6 | Forward to ETR Bit |
| M | ecm-M | 7 | Destined to Map-Server Bit |
+-----------+-----------+--------------+----------------------------+
LISP Encapsulated Control Message (ECM) Header Bits
Sub-Registry: EID-Record Header Bits [Section 5.4]:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Locator Count | EID mask-len | ACT |A| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-----------+--------------+--------------+-------------------+
| Spec Name | IANA Name | Bit Position | Description |
+-----------+--------------+--------------+-------------------+
| A | eid-record-A | 19 | Authoritative Bit |
+-----------+--------------+--------------+-------------------+
LISP EID-Record Header Bits
Sub-Registry: RLOC-Record Header Bits [Section 5.4]:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unused Flags |L|p|R| Loc-AFI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-----------+---------------+--------------+----------------------+
| Spec Name | IANA Name | Bit Position | Description |
+-----------+---------------+--------------+----------------------+
| L | rloc-record-L | 13 | Local RLOC Bit |
| p | rloc-record-p | 19 | RLOC-Probe Reply Bit |
| R | rloc-record-R | 19 | RLOC Reachable Bit |
+-----------+---------------+--------------+----------------------+
LISP RLOC-Record Header Bits
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13. References
13.1. Normative References
[I-D.ietf-lisp-6834bis]
Iannone, L., Saucez, D., and O. Bonaventure, "Locator/ID
Separation Protocol (LISP) Map-Versioning", draft-ietf-
lisp-6834bis-02 (work in progress), September 2018.
[I-D.ietf-lisp-rfc6830bis]
Farinacci, D., Fuller, V., Meyer, D., Lewis, D., and A.
Cabellos-Aparicio, "The Locator/ID Separation Protocol
(LISP)", draft-ietf-lisp-rfc6830bis-24 (work in progress),
October 2018.
[RFC2404] Madson, C. and R. Glenn, "The Use of HMAC-SHA-1-96 within
ESP and AH", RFC 2404, DOI 10.17487/RFC2404, November
1998, .
[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005,
.
[RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA-
384, and HMAC-SHA-512 with IPsec", RFC 4868,
DOI 10.17487/RFC4868, May 2007,
.
[RFC4984] Meyer, D., Ed., Zhang, L., Ed., and K. Fall, Ed., "Report
from the IAB Workshop on Routing and Addressing",
RFC 4984, DOI 10.17487/RFC4984, September 2007,
.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
.
[RFC6071] Frankel, S. and S. Krishnan, "IP Security (IPsec) and
Internet Key Exchange (IKE) Document Roadmap", RFC 6071,
DOI 10.17487/RFC6071, February 2011,
.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, .
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13.2. Informative References
[AFI] IANA, "Address Family Identifier (AFIs)", ADDRESS FAMILY
NUMBERS http://www.iana.org/assignments/address-family-
numbers/address-family-numbers.xhtml?, Febuary 2007.
[GTP-3GPP]
3GPP, "General Packet Radio System (GPRS) Tunnelling
Protocol User Plane (GTPv1-U)", TS.29.281
https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=1699, January
2015.
[I-D.herbert-intarea-ila]
Herbert, T. and P. Lapukhov, "Identifier-locator
addressing for IPv6", draft-herbert-intarea-ila-01 (work
in progress), March 2018.
[I-D.ietf-lisp-ecdsa-auth]
Farinacci, D. and E. Nordmark, "LISP Control-Plane ECDSA
Authentication and Authorization", draft-ietf-lisp-ecdsa-
auth-00 (work in progress), September 2018.
[I-D.ietf-lisp-eid-anonymity]
Farinacci, D., Pillay-Esnault, P., and W. Haddad, "LISP
EID Anonymity", draft-ietf-lisp-eid-anonymity-03 (work in
progress), October 2018.
[I-D.ietf-lisp-eid-mobility]
Portoles-Comeras, M., Ashtaputre, V., Moreno, V., Maino,
F., and D. Farinacci, "LISP L2/L3 EID Mobility Using a
Unified Control Plane", draft-ietf-lisp-eid-mobility-02
(work in progress), May 2018.
[I-D.ietf-lisp-gpe]
Maino, F., Lemon, J., Agarwal, P., Lewis, D., and M.
Smith, "LISP Generic Protocol Extension", draft-ietf-lisp-
gpe-06 (work in progress), September 2018.
[I-D.ietf-lisp-introduction]
Cabellos-Aparicio, A. and D. Saucez, "An Architectural
Introduction to the Locator/ID Separation Protocol
(LISP)", draft-ietf-lisp-introduction-13 (work in
progress), April 2015.
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[I-D.ietf-lisp-mn]
Farinacci, D., Lewis, D., Meyer, D., and C. White, "LISP
Mobile Node", draft-ietf-lisp-mn-04 (work in progress),
October 2018.
[I-D.ietf-lisp-pubsub]
Rodriguez-Natal, A., Ermagan, V., Leong, J., Maino, F.,
Cabellos-Aparicio, A., Barkai, S., Farinacci, D.,
Boucadair, M., Jacquenet, C., and S. Secci, "Publish/
Subscribe Functionality for LISP", draft-ietf-lisp-
pubsub-01 (work in progress), October 2018.
[I-D.ietf-lisp-sec]
Maino, F., Ermagan, V., Cabellos-Aparicio, A., and D.
Saucez, "LISP-Security (LISP-SEC)", draft-ietf-lisp-sec-16
(work in progress), October 2018.
[I-D.ietf-nvo3-vxlan-gpe]
Maino, F., Kreeger, L., and U. Elzur, "Generic Protocol
Extension for VXLAN", draft-ietf-nvo3-vxlan-gpe-06 (work
in progress), April 2018.
[I-D.ietf-opsec-icmp-filtering]
Gont, F., Gont, G., and C. Pignataro, "Recommendations for
filtering ICMP messages", draft-ietf-opsec-icmp-
filtering-04 (work in progress), July 2013.
[I-D.meyer-loc-id-implications]
Meyer, D. and D. Lewis, "Architectural Implications of
Locator/ID Separation", draft-meyer-loc-id-implications-01
(work in progress), January 2009.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, .
[RFC1071] Braden, R., Borman, D., and C. Partridge, "Computing the
Internet checksum", RFC 1071, DOI 10.17487/RFC1071,
September 1988, .
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997,
.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
.
[RFC2890] Dommety, G., "Key and Sequence Number Extensions to GRE",
RFC 2890, DOI 10.17487/RFC2890, September 2000,
.
[RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and SHA-based HMAC and HKDF)", RFC 6234,
DOI 10.17487/RFC6234, May 2011,
.
[RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
Locator/ID Separation Protocol (LISP)", RFC 6830,
DOI 10.17487/RFC6830, January 2013,
.
[RFC6831] Farinacci, D., Meyer, D., Zwiebel, J., and S. Venaas, "The
Locator/ID Separation Protocol (LISP) for Multicast
Environments", RFC 6831, DOI 10.17487/RFC6831, January
2013, .
[RFC6832] Lewis, D., Meyer, D., Farinacci, D., and V. Fuller,
"Interworking between Locator/ID Separation Protocol
(LISP) and Non-LISP Sites", RFC 6832,
DOI 10.17487/RFC6832, January 2013,
.
[RFC6836] Fuller, V., Farinacci, D., Meyer, D., and D. Lewis,
"Locator/ID Separation Protocol Alternative Logical
Topology (LISP+ALT)", RFC 6836, DOI 10.17487/RFC6836,
January 2013, .
[RFC6837] Lear, E., "NERD: A Not-so-novel Endpoint ID (EID) to
Routing Locator (RLOC) Database", RFC 6837,
DOI 10.17487/RFC6837, January 2013,
.
[RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
Morris, J., Hansen, M., and R. Smith, "Privacy
Considerations for Internet Protocols", RFC 6973,
DOI 10.17487/RFC6973, July 2013,
.
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[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
.
[RFC7835] Saucez, D., Iannone, L., and O. Bonaventure, "Locator/ID
Separation Protocol (LISP) Threat Analysis", RFC 7835,
DOI 10.17487/RFC7835, April 2016,
.
[RFC8060] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical
Address Format (LCAF)", RFC 8060, DOI 10.17487/RFC8060,
February 2017, .
[RFC8111] Fuller, V., Lewis, D., Ermagan, V., Jain, A., and A.
Smirnov, "Locator/ID Separation Protocol Delegated
Database Tree (LISP-DDT)", RFC 8111, DOI 10.17487/RFC8111,
May 2017, .
[RFC8113] Boucadair, M. and C. Jacquenet, "Locator/ID Separation
Protocol (LISP): Shared Extension Message & IANA Registry
for Packet Type Allocations", RFC 8113,
DOI 10.17487/RFC8113, March 2017,
.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, .
[RFC8378] Moreno, V. and D. Farinacci, "Signal-Free Locator/ID
Separation Protocol (LISP) Multicast", RFC 8378,
DOI 10.17487/RFC8378, May 2018,
.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, .
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Appendix A. Acknowledgments
The original authors would like to thank Greg Schudel, Darrel Lewis,
John Zwiebel, Andrew Partan, Dave Meyer, Isidor Kouvelas, Jesper
Skriver, Fabio Maino, and members of the lisp@ietf.org mailing list
for their feedback and helpful suggestions.
Special thanks are due to Noel Chiappa for his extensive work and
thought about caching in Map-Resolvers.
The current authors would like to give a sincere thank you to the
people who help put LISP on standards track in the IETF. They
include Joel Halpern, Luigi Iannone, Deborah Brungard, Fabio Maino,
Scott Bradner, Kyle Rose, Takeshi Takahashi, Sarah Banks, Pete
Resnick, Colin Perkins, Mirja Kuhlewind, Francis Dupont, Benjamin
Kaduk, Eric Rescorla, Alvaro Retana, Alexey Melnikov, Alissa Cooper,
Suresh Krishnan, Alberto Rodriguez-Natal, Vina Ermagen, Mohamed
Boucadair, Brian Trammell, Sabrina Tanamal, and John Drake. The
contributions they offered greatly added to the security, scale, and
robustness of the LISP architecture and protocols.
Appendix B. Document Change Log
[RFC Editor: Please delete this section on publication as RFC.]
B.1. Changes to draft-ietf-lisp-rfc6833bis-18
o Posted mid October 2018.
o Added Fabio text to the Security Considerations section.
B.2. Changes to draft-ietf-lisp-rfc6833bis-18
o Posted mid October 2018.
o Fixed comments from Eric after more email clarity.
B.3. Changes to draft-ietf-lisp-rfc6833bis-17
o Posted early October 2018.
o Changes to reflect comments from Sep 27th Telechat.
o Added all flag bit definitions as request for allocation in IANA
Considersations section.
o Added an applicability statement in section 1 to address security
concerns from Telechat.
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o Moved m-bit description and IANA request to draft-ietf-lisp-mn.
o Moved I-bit description and IANA request to draft-ietf-lisp-
pubsub.
B.4. Changes to draft-ietf-lisp-rfc6833bis-16
o Posted Late-September 2018.
o Re-wrote Security Considerations section. Thanks Albert.
o Added Alvaro text to be more clear about IANA actions.
B.5. Changes to draft-ietf-lisp-rfc6833bis-15
o Posted mid-September 2018.
o Changes to reflect comments from Colin and Mirja.
B.6. Changes to draft-ietf-lisp-rfc6833bis-14
o Posted September 2018.
o Changes to reflect comments from Genart, RTGarea, and Secdir
reviews.
B.7. Changes to draft-ietf-lisp-rfc6833bis-13
o Posted August 2018.
o Final editorial changes before RFC submission for Proposed
Standard.
o Added section "Changes since RFC 6833" so implementators are
informed of any changes since the last RFC publication.
B.8. Changes to draft-ietf-lisp-rfc6833bis-12
o Posted late July 2018.
o Moved RFC6830bis and RFC6834bis to Normative References.
B.9. Changes to draft-ietf-lisp-rfc6833bis-11
o Posted July 2018.
o Fixed Luigi editorial comments to ready draft for RFC status and
ran through IDNITs again.
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B.10. Changes to draft-ietf-lisp-rfc6833bis-10
o Posted after LISP WG at IETF week March.
o Move AD field encoding after S-bit in the ECM packet format
description section.
o Say more about when the new Drop actions should be sent.
B.11. Changes to draft-ietf-lisp-rfc6833bis-09
o Posted March IETF week 2018.
o Fixed editorial comments submitted by document shepherd Luigi
Iannone.
B.12. Changes to draft-ietf-lisp-rfc6833bis-08
o Posted March 2018.
o Added RLOC-probing algorithm.
o Added Solicit-Map Request algorithm.
o Added several mechanisms (from 6830bis) regarding Routing Locator
Reachability.
o Added port 4342 to IANA Considerations section.
B.13. Changes to draft-ietf-lisp-rfc6833bis-07
o Posted December 2017.
o Make it more clear in a couple of places that RLOCs are used to
locate ETRs more so than for Map-Server Map-Request forwarding.
o Make it clear that "encapsualted" for a control message is an ECM
based message.
o Make it more clear what messages use source-port 4342 and which
ones use destinatino-port 4342.
o Don't make DDT references when the mapping transport system can be
of any type and the referneced text is general to it.
o Generalize text when referring to the format of an EID-prefix.
Can use othe AFIs then IPv4 and IPv6.
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o Many editorial changes to clarify text.
o Changed some "must", "should", and "may" to capitalized.
o Added definitions for Map-Request and Map-Reply messages.
o Ran document through IDNITs.
B.14. Changes to draft-ietf-lisp-rfc6833bis-06
o Posted October 2017.
o Spec the I-bit to include the xTR-ID in a Map-Request message to
be consistent with the Map-Register message and to anticipate the
introduction of pubsub functionality to allow Map-Requests to
subscribe to RLOC-set changes.
o Updated references for individual submissions that became working
group documents.
o Updated references for working group documents that became RFCs.
B.15. Changes to draft-ietf-lisp-rfc6833bis-05
o Posted May 2017.
o Update IANA Considerations section based on new requests from this
document and changes from what was requested in [RFC6830].
B.16. Changes to draft-ietf-lisp-rfc6833bis-04
o Posted May 2017.
o Clarify how the Key-ID field is used in Map-Register and Map-
Notify messages. Break the 16-bit field into a 8-bit Key-ID field
and a 8-bit Algorithm-ID field.
o Move the Control-Plane codepoints from the IANA Considerations
section of RFC6830bis to the IANA Considerations section of this
document.
o In the "LISP Control Packet Type Allocations" section, indicate
how message Types are IANA allocated and how experimental RFC8113
sub-types should be requested.
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B.17. Changes to draft-ietf-lisp-rfc6833bis-03
o Posted April 2017.
o Add types 9-14 and specify they are not assigned.
o Add the "LISP Shared Extension Message" type and point to RFC8113.
B.18. Changes to draft-ietf-lisp-rfc6833bis-02
o Posted April 2017.
o Clarify that the LISP Control-Plane document defines how the LISP
Data-Plane uses Map-Requests with either the SMR-bit set or the
P-bit set supporting mapping updates and RLOC-probing. Indicating
that other Data-Planes can use the same mechanisms or their own
defined mechanisms to achieve the same functionality.
B.19. Changes to draft-ietf-lisp-rfc6833bis-01
o Posted March 2017.
o Include references to new RFCs published.
o Remove references to self.
o Change references from RFC6830 to RFC6830bis.
o Add two new action/reasons to a Map-Reply has posted to the LISP
WG mailing list.
o In intro section, add refernece to I-D.ietf-lisp-introduction.
o Removed Open Issues section and references to "experimental".
B.20. Changes to draft-ietf-lisp-rfc6833bis-00
o Posted December 2016.
o Created working group document from draft-farinacci-lisp
-rfc6833-00 individual submission. No other changes made.
B.21. Changes to draft-farinacci-lisp-rfc6833bis-00
o Posted November 2016.
o This is the initial draft to turn RFC 6833 into RFC 6833bis.
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o The document name has changed from the "Locator/ID Separation
Protocol (LISP) Map-Server Interface" to the "Locator/ID
Separation Protocol (LISP) Control-Plane".
o The fundamental change was to move the Control-Plane messages from
RFC 6830 to this document in an effort so any IETF developed or
industry created Data-Plane could use the LISP mapping system and
Control-Plane.
o Update Control-Plane messages to incorporate what has been
implemented in products during the early phase of LISP development
but wasn't able to make it into RFC6830 and RFC6833 to make the
Experimental RFC deadline.
o Indicate there may be nodes in the mapping system that are not MRs
or MSs, that is a ALT-node or a DDT-node.
o Include LISP-DDT in Map-Resolver section and explain how they
maintain a referral-cache.
o Removed open issue about additional state in Map-Servers. With
[RFC8111], Map-Servers have the same registration state and can
give Map-Resolvers complete information in ms-ack Map-Referral
messages.
o Make reference to the LISP Threats Analysis RFC [RFC7835].
Authors' Addresses
Vince Fuller
Cisco Systems
EMail: vaf@vaf.net
Dino Farinacci
Cisco Systems
EMail: farinacci@gmail.com
Albert Cabellos
UPC/BarcelonaTech
Campus Nord, C. Jordi Girona 1-3
Barcelona, Catalunya
Spain
EMail: acabello@ac.upc.edu
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